JPS649258B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a kiln for producing cement powder raw materials such as limestone, clay, and silica stone, or powder raw materials such as limestone and alumina alone (hereinafter referred to as powder raw materials for cement, etc.). .

Typical prior art is a so-called suspension-type raw material preheating device equipped with a calciner with an independent heat source, in which powdered raw materials such as cement that have been calcined to almost 100% are calcined in a rotary kiln. There is a technology that cools clinker and extracts it as a product. In this prior art, heat transfer in the rotary kiln occurs at the contact portion between the surface portion of the deposited raw material layer and the wall surface of the rotary kiln, so the heat transfer area is relatively small. Therefore, the heat transfer efficiency is poor and the rotary kiln becomes large. As a result, the heat radiation loss from the rotary kiln is large and the installation area becomes large.

An object of the present invention is to provide a kiln for firing cement clinker, etc., which solves the above-mentioned technical problems.

The present invention is a fluidized firing furnace for fluidizing powder raw materials such as cement in a fluidized bed on a dispersing means using the combustion heat of fuel, and the dispersing means has a concentric step shape that becomes lower toward the center. This dispersion plate has a hole that guides the gas from the gas chamber provided below the dispersion plate upward and radially inward, and a large hole is formed in the center of the dispersion plate. This is a fluidized fluidized kiln for cement clinker, etc., which is connected to a chute for discharging lumps.

In a preferred embodiment, the dispersion means includes a central disc-shaped dispersion plate that allows gas to flow upward, and concentric step-shaped dispersion plates that move upward in a radial direction from the dispersion plate. a plurality of annular dispersion plates arranged to allow gas to flow upward; and a cylindrical shape that interconnects each dispersion plate to extend vertically and allow gas to flow radially inward. It is characterized by being composed of a dispersion plate.

Further, in a preferred embodiment, the space below the dispersion means is divided into a plurality of spaces by partition plates corresponding to the cylindrical dispersion plate.

Further, in a preferred embodiment, air blowing pipes are connected to each of the cylindrical distribution plates at intervals in the circumferential direction.

Further, in a preferred embodiment, a gas fuel supply pipe is connected to the space below the dispersion means.

Further, in a preferred embodiment, the space below the dispersion means is divided into a plurality of parts by a plurality of radially extending partition plates.

In a preferred embodiment, a duct for supplying air and a gas fuel supply pipe for supplying gas fuel are alternately connected to each of the plurality of divided spaces below the dispersion means. do.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram of an embodiment of the present invention.
In FIG. 1, the flow of solids such as cement raw materials is shown by solid line arrows, and the flow of gases such as combustion exhaust gas is shown by broken line arrows. Powder raw materials such as cement are preheated in a preheating device 2 equipped with a calcination furnace 1 by floating in the combustion exhaust gas from the fluidized calcination furnace 4 and the calcination furnace 1, and then calcined in the calcination furnace 1. be done. Almost completely calcined powder raw material (hereinafter referred to as calcined raw material)
is charged into the fluidized fluidized firing furnace 4. In this fluidized firing furnace 4, the calcined raw material is fired while forming a fluidized bed 8, and the produced clinker is cooled in a cooling device 7 and then taken out as a product.

On the other hand, among the cooling air introduced into the cooling device 7, the air heated to a relatively high temperature through heat exchange with the clinker is led through the duct 9 as combustion air to the calciner 1. . Furthermore, the air heated to a relatively low temperature in the cooling device 7 is guided through the duct 10 as fluidization air and combustion air to the fluidized fluidized kiln 4 . The combustion exhaust gas from the fluidized fluidized furnace 4 is led to the preheating device 2 via the duct 5, where it exchanges heat with the powder raw material and is then discharged.

The preheating device 2 includes a floating heat exchanger 13 and a calcining furnace 1.
It consists of The floating heat exchanger 13 is composed of collectors C1 to C5, such as cyclones, arranged in five upper and lower stages, and each collector C1 to C5 is connected to a duct D2 to C5.
They are connected at D5. Furthermore, the collector C1 at the lowest stage and the calciner 1 are connected via a duct D1.

In such a preheating device 2, the combustion exhaust gas from the burner 11 in the calcination furnace 1 and the combustion exhaust gas from the fluidized fluidized calcination furnace 4 are transported through the duct D1 → collector C1 → duct D2 → collector C2 → duct D3 → collector C3
→ Duct D4 → Collector C4 → Duct D5 → Collector C5 and is discharged through circulation in this order. On the other hand, duct D
The powder raw material inputted into the duct D5 from the input hopper 14 connected in the middle of 5 is collected in the following order: collector C5 → duct D4 → collector C4 → duct D3 → collector C3 →
While descending sequentially from the duct D2 to the collector C2, the gas is preheated by exchanging heat with the exhaust gas, and then put into the calcining furnace 1. After the powder raw material is almost completely calcined in this calcining furnace 1, it is fed into a fluidized fluidized calcining furnace 4 from a chute 3 via a collector C1.

FIG. 2 is a cross-sectional view of the fluidized fluidized kiln 4 seen from the section line - in FIG. 1. The casing 17 of the fluidized fluidized kiln 4 is constructed by, for example, an upright cylindrical casing upper part 17a and a casing lower part 17b having a larger diameter than the casing upper part 17a connected concentrically by an annular connecting plate 15. Ru. A dispersion means 18 is provided in the lower part of the casing 17, and a space 19 is formed below the dispersion means 18. A duct 5 is connected to the top of the casing 17, and this duct 5 is connected to a separator 6. The separator 6 is provided below the calciner 1 , and the bottom of the calciner 1 and the separator 6 are connected via a rising duct 16 .

The dispersion means 18 includes a disc-shaped dispersion plate 20 arranged at the center, a cylindrical dispersion plate 21 connected to the peripheral edge of the dispersion plate 20 and extending upward, and connected to the upper end of the dispersion plate 21. an annular dispersion plate 22 arranged concentrically with the dispersion plate 20; and a cylindrical dispersion plate 23 connected to the peripheral edge of the dispersion plate 22 and extending upward.
a dispersion plate 24 connected to the upper end of the dispersion plate 23 and arranged concentrically with the dispersion plate 20; and a casing upper part 17 connected to the peripheral edge of the dispersion plate 24 and extending upward.
and a cylindrical dispersion plate 25 connected to the lower end of a. The dispersion plate 25 forms an annular space 32 between it and the inner surface of the lower casing 17b. In this way, the dispersing means 18 is formed in a concentric step shape that becomes harder toward the center inside the casing 17, and a fluidized bed 8 of the calcined raw material and clinker is formed on the dispersing means 18.

The space 19 is formed by cylindrical partition plates 26, 27, 28 extending downward from the lower ends of the dispersion plates 21, 23, 25.
The space 19 is divided by
is divided into four air chamber sections 29, 30, 31, 32. Air supply ducts 37 to 40 each having individual flow rate adjustment dampers 33 to 36 are connected to each of the air chamber portions 29 to 32, and each of the air supply ducts 37 to 40 is commonly connected to the duct 10.

A casing upper part 17 corresponding to the upper part of the fluidized bed 8
An overflow pipe 41 for discharging generated clinker is connected to the side wall of a. Further, a chute 42 for discharging large lumps is connected to the dispersing plate 20 at the center of the dispersing means 18. Note that dampers 43 and 44 are provided in the middle of the overflow pipe 41 and the chute 42, respectively.
Further, a plurality of burners 45 are provided in the upper part 17a of the casing at intervals in the circumferential direction and facing into the fluidized bed 8. Fuel such as pulverized coal or crude gas obtained by gasifying coal is blown into the fluidized bed 8 from these burners 45 .

In the fluidized firing furnace 4, the calcined raw material input from the chute 3 is fluidized by the air flowing upward through the dispersion means 18, and is heated to a temperature of 1,400 to
Fired at 1500℃. In this fluidized firing furnace 4, the dispersing means 18 is formed in a step-like manner, and fluidizing air is blown from the dispersing plates 21, 23, 25 toward the center of the fluidized bed 8. is divided into four air chamber sections 29-32, and the amount of air blown into each air chamber section 29-32 is adjusted by flow rate adjustment dampers 33-36. Therefore, the clinker and the unfired raw material in the fluidized bed 8 convect within the fluidized bed 8 as shown by the solid arrows, and mixing between the central part and the peripheral part of the fluidized bed 8 becomes good. Therefore, the fuel blown from the burner 45 is reliably dispersed within the fluidized bed 8 and burned well, and the temperature distribution of the fluidized bed 8 becomes uniform accordingly. In such a fluidized bed 8, a part of the calcined raw material melts and aggregates, becomes a nucleus or adheres to the remaining clinker particles, and is granulated and fired. Moreover, since the fluidity is good, the occurrence of coatings and large lumps is prevented as much as possible, the movement of particle groups is improved, and adhesion between particles is prevented, and a good clinker with a uniform particle shape is obtained. Enables long-term stable continuous operation.

A portion of the clinker and unfired raw materials fired in the fluidized fluidized furnace 4 are discharged through an overflow pipe 41. Furthermore, even if the clinker particles grow too much in the fluidized bed 8 and become coarse, the clinker particles will roll on the dispersion means 18 and move to the dispersion plate 20 in the center.
and is discharged from the chute 42. This large lump of clinker may be cooled by being put into a cooler (not shown), such as a packed bed cooler. The exhaust gas from the fluidized fluidized firing furnace 4 is led to a separator 6 through a duct 5, and the unfired raw material accompanying the exhaust gas is collected by the separator 6. This collected unfired raw material is returned to the fluidized fluidized furnace 4 via the chute 46 and refired. The exhaust gas from which dust has been removed by the separator 6 is led to the calciner 1 through the riser duct 16, and is discharged after exchanging heat with the powder raw material together with the combustion exhaust gas from the calciner 1 in the preheating device 2.

A casing 51 of the cooling device 7 is in the shape of a sealed box extending in the lateral direction, and a dispersion plate 52 is provided at a lower portion inside the casing 51 . According to this embodiment, the lower part of the distribution plate 52 is divided into two, and cooling air chambers 53 and 54 are provided, respectively. Forced air blowers 55 and 56 are connected to the cooling air chambers 53 and 54, respectively.

The fluidized bed 57 formed above the distribution plate 52 is
It is divided into multiple parts to efficiently cool the high temperature clinker. For example, in FIG. 1, the portions of the fluidized bed 57 corresponding to the cooling air chambers 53 and 54 are each divided into two parts. Also, casing 5
1, the space above the fluidized bed 57 is divided by an overpartition 58 corresponding to a relatively high temperature air recovery area, and one space 59 has a chute 48 and a rising duct 49.
are connected to each other. Further, an air exhaust pipe 61 is connected to the other space 60. By dividing the upper part of the casing 51 in this way, the space 59
The air introduced into the space 60 is led to the riser duct 49, and the air introduced into the space 60 is led to the air exhaust pipe 61.
guided by.

The rising duct 49 extends upward from one end of the casing 51, and its upper end is connected to the separator 70. The separator 70 is further connected to a duct 9 having a separator 71 in the middle.
The lower end of the overflow pipe 41 is connected to the rising duct 4
The produced clinker from the fluidized bed 8 is thrown into the high temperature air flowing upward through the riser duct 49 together with the unfired raw material. The clinker containing this unfired raw material is suspended in the high temperature air and introduced into the separator 70 from the rising duct 49, and the coarse clinker is separated from the separator 70.
The liquid is separated within the casing 51 through a chute 48 provided with a damper 47 after settling by gravity. In this way, the hot clinker is cooled in the riser duct 49 and the separator 70 by contacting relatively high temperature air from the cooling device 7 before being introduced into the cooling device 7 .

The clinker introduced into the casing 51 of the cooling device 7 is cooled while moving inside the fluidized bed 57 from one end to the other end (from the left end to the right end in FIG. 1), and then passes through the overflow pipe 50. is extracted as a product. Moreover, the clinker fed from the fluidized bed 57 through the overflow pipe 41 and the separator 70 does not contain large lumps and has a relatively uniform particle size, so air blow-through is unlikely to occur in the fluidized bed 57. In the fluidized bed 57, the clinker is efficiently cooled.

Air exhaust pipe 61 is connected to duct 10 . This duct 10 has a dust collector 73 and a blower 7 in its middle.
4 and are connected to the air supply ducts 37 to 40, respectively.

As mentioned above, in the cooling device 7, the air that has been heated to a relatively low temperature by heat exchange with the clinker is used as fluidization air and combustion air in the fluidized fluidized kiln 4, and the air that has been heated to a relatively high temperature is Since the air is used as combustion air in the calciner 1, the sensible heat of the clinker is sufficiently recovered, improving thermal efficiency.
Incidentally, of the air heated to a relatively low temperature, the remaining air after being supplied to the fluidized fluidized firing furnace 4 is discharged through a discharge pipe 63 branched from the duct 10.

The unfired raw materials and fine clinker entrained in the high-temperature air led out from the separator 70 to the duct 9 are collected by the separator 71 and then returned to the fluidized fluidized kiln 4 via the chute 72. Note that a vertically movable collision plate 75 is provided at the connection portion between the rising duct 49 and the separator 70, and this collision plate 75
By adjusting the amount of protrusion, the clinker separation rate in the separator 70 can be changed. By doing so, the amount of clinker returned to the fluidized kiln 4 can be adjusted.

As another embodiment of the present invention, at least a part of the calcined raw material collected by the lowermost collector C1 in the preheating device 2 is transferred to the duct 5 through the chute 76.
The temperature of the exhaust gas flowing through the duct 5 may be lowered to below the liquid phase formation temperature of the clinker. By doing so, coaching troubles in the duct 5 and the separator 6 can be prevented.

FIG. 3 is a system diagram of another embodiment of the present invention,
FIG. 4 is a sectional view taken along the section line - in FIG. 3, and parts corresponding to the embodiments in FIGS. 1 and 2 are given the same reference numerals. In this example,
The casing 17 of the fluidized fluidized furnace 4 is formed into an upright cylindrical shape. The dispersion means 80 provided at the lower part of the fluidized firing furnace 4 includes a disc-shaped dispersion plate 81 disposed in the center, and a cylindrical dispersion plate 82 extending upward from the peripheral edge of the dispersion plate 81. , an annular dispersion plate 83 connected to the upper end of the dispersion plate 82;
3, and an annular dispersion plate 85 connected to the upper end of the dispersion plate 84 and having its circumferential edge fixed to the inner surface of the casing 17. Moreover, each dispersion plate 81, 8
3 and 85 are formed in a conical shape that becomes smaller in diameter toward the center of the casing 17. Further, on the side wall of the casing 17 above each of the distribution plates 82 and 84 and the distribution plate 85, air blowing pipes 86 and 87 are provided at intervals in the circumferential direction.
88 are connected to each other. These air blowing pipes 86, 87, 88 are connected to headers 89, 90, 9 surrounding the distribution plates 82, 84 and the casing 17.
1, respectively. Each header 89, 90,
Ducts 95, 96, 97 each having dampers 92, 93, 94 are connected to the duct 91.
Commonly connected to 0.

According to this embodiment, the distribution plates 81, 83, 85
is inclined so that it becomes lower toward the center, and air is blown inward in the radial direction from the air blowing pipes 86, 87, and 88.
Clinker that has become coarse during granulation and firing in the fluidized bed 8 is easily discharged from the chute 42 in the center of the fluidized bed 8.

FIG. 5 is a system diagram of another embodiment of the present invention,
FIG. 6 is a sectional view taken along the folding line in FIG. 5, and parts corresponding to the embodiments in FIGS. 1 and 2 are given the same reference numerals. This embodiment is similar to the embodiments shown in FIGS. 1 and 2 described above, but it should be noted that the air chamber portions 29 to 32 formed below the dispersion means 18 are partition plates having a number of radial extensions. It is further divided by 100.
(FIG. 6) Moreover, each air chamber portion 101, 102, 1 adjacent to each other in the radial direction of the casing 17
03, 104 have dampers 105, 106, 10
Air supply ducts 10 each comprising 7 and 108
9, 110, 111, and 112 are connected to each other, and their air supply ducts 109 to 112 are commonly connected to the duct 10. Further, each of the air chamber portions 101 to 104 that are adjacent to each other along the radial direction of the casing 17 is combined into one block 113.
As a result, the amount of air blown into this block 113 is sequentially changed over time along the circumferential direction of the casing 17. By doing so, the fluidized firing furnace 4
The mixing effect within the fluidized bed 8 is further enhanced.

FIG. 7 is a sectional view corresponding to the above-described FIG. 6 of another embodiment of the present invention. According to this embodiment, each air chamber portion divided by the partition plates 26, 27, 28 extends radially from the partition plates 115, 116, 1.
17,118. Moreover, those partition plates 115 to 118 are connected to the casing 17.
are arranged offset along the circumferential direction. Furthermore, air chamber portions (shown with diagonal lines) 120, 121, 122, 123 at positions shifted from each other along the circumferential direction
The amount of air blown into each block is changed sequentially along the circumferential direction. This will further enhance the mixing effect within the fluidized bed 8.

As another embodiment of the present invention, the casing 125 of the fluidized firing furnace 4 has a rectangular cross section as shown in FIG.
The space 19 may be divided into multiple parts. Moreover, the air chamber portions (indicated by diagonal lines) 126, 127, 128, and 129 at mutually shifted positions in the circumferential direction are treated as one block, and the amount of air blown into that block is sequentially changed over time along the circumferential direction. . In this embodiment as well, the mixing effect of the fluidized bed 8 is enhanced as in the embodiment shown in FIG. 7 described above.

FIG. 9 is a system diagram of another embodiment of the present invention,
FIG. 10 is a cross-sectional view taken along the section line - in FIG. 9, and parts corresponding to the respective embodiments described above are given the same reference numerals. This embodiment is similar to the embodiment of FIGS. 5 and 6 described above, but it should be noted that the air chamber sections 101-104 and the gas fuel chamber section 1
31 to 134 are provided alternately in the circumferential direction. Each air chamber portion 101 to 104 has an air supply duct 1 as in the embodiment shown in FIGS. 5 and 6.
09 to 112 are connected to each other, and gas fuel supply pipes 135 to 1 are connected to the gas fuel chambers 131 to 134, respectively.
38 are connected to each other. These gas fuel supply pipes 135 to 138 are connected to flow control valves 139 to 142.
, and are commonly connected to a gas fuel supply source 143.

According to this embodiment, since a flame is formed on the dispersion means 18 by combustion of the gas fuel, a high temperature and substantially uniform temperature region is formed on the dispersion means 18. Therefore, adhesion of the clinker melt component to the dispersing means 18 is prevented.

Furthermore, in the embodiments of FIGS. 9 and 10,
The space 19 may be partitioned as in the embodiment shown in FIG.

FIG. 11 is a system diagram of another embodiment of the present invention, and FIG. 12 is a cross-sectional view taken from section line XII--XII in FIG. The same references are given. This embodiment is similar to the embodiment of FIGS. 3 and 4, but it should be noted that a flow control valve 14 is provided in each air chamber section 29-31.
4, 146, 147, respectively, are connected to gas fuel supply pipes 148-150. Each gas fuel supply pipe 148 - 150 is commonly connected to a gas combustion material supply source 152 .

This embodiment also provides the same effects as the embodiments shown in FIGS. 9 and 10.

Note that the fluidized firing furnace 4 can be widely implemented as a fluidized firing furnace for cement clinker and the like, as well as a firing device configured as in each of the above-described embodiments.

As described above, according to the present invention, the dispersing means of the present fluidized firing furnace is formed in a step-like shape that becomes lower toward the center, and the fluidizing gas flows upward through the dispersing means, and at the same time Flows inward. Therefore, the central part and the peripheral part of the fluidized bed are better mixed, and the temperature distribution of the fluidized bed becomes uniform. As a result, the occurrence of large lumps or coating can be prevented as much as possible, and long-term stable continuous operation becomes possible. Furthermore, even if a large lump occurs, the large lump rolls on the dispersion means, falls into the center, and is discharged from the chute, so that it does not interfere with operation.

[Brief explanation of drawings]

Fig. 1 is a system diagram of one embodiment of the present invention, Fig. 2 is a sectional view taken from the cutting plane line in Fig. 1, Fig. 3 is a system diagram of another embodiment of the present invention, and Fig. 4 is a cross-sectional view taken from the cutting plane line in FIG. 3, FIG. 5 is a system diagram of another embodiment of the present invention, FIG. 6 is a cross-sectional view taken from the cutting plane line in FIG. 8 is a sectional view of another embodiment of the invention, FIG. 9 is a system diagram of another embodiment of the invention, and FIG. 10 is a sectional view of another embodiment of the invention. 11 is a system diagram of another embodiment of the present invention, and FIG. 12 is a sectional view taken from the section line XII--XII in FIG. 11. 4...Fluidized firing furnace, 8...Fluidized bed, 18,80
... Dispersion means, 19 ... Space, 20-25, 81
~85... Dispersion plate, 26~28,100,115
~118... Partition plate, 29~32, 101~10
4,120-123...Air chamber part, 86-68
...Air blowing pipe, 131-134...Gas fuel chamber portion, 135-138, 148-150...Gas fuel supply pipe.

Claims (1)

[Claims] 1. A fluidized firing furnace in which powdered raw materials such as cement are fluidized and fired in a fluidized bed on a dispersing means using the combustion heat of fuel, wherein the dispersing means becomes lower toward the center. The dispersion plate has a concentric step-shaped dispersion plate, and a hole is formed in the dispersion plate to guide gas upward and radially inward from the gas chamber provided below the dispersion plate, and a hole is formed in the center of the dispersion plate. A fluidized kiln for cement clinker, etc., which is characterized in that a chute is connected to the chute for discharging large lumps. 2. The dispersion means includes a disc-shaped dispersion plate at the center that allows gas to flow upward, and a dispersion plate arranged in a concentric step shape so that the dispersion plate reaches an upward position as it goes radially outward from the dispersion plate. a plurality of annular dispersion plates that allow gas to flow inward; and a cylindrical dispersion plate that interconnects each of the dispersion plates and extends vertically to allow gas to flow inward in the radial direction. Claim 1 consisting of
Fluidized fluidized kiln for cement clinker, etc. as described in Section 2. 3. A fluidized kiln for cement clinker or the like according to claim 2, wherein the space below the dispersion means is divided into a plurality of parts by partition plates corresponding to the cylindrical dispersion plate. . 4. The fluidized firing method for cement clinker or the like according to claim 2 or 3, wherein air blowing pipes are connected to the cylindrical distribution plate at intervals in the circumferential direction. Furnace. 5. The fluidized kiln for cement clinker or the like according to claim 4, wherein a gas fuel supply pipe is connected to the space below the dispersion means. 6. The cement clinker according to claim 1, 2 or 3, wherein the space below the dispersion means is divided into a plurality of parts by a plurality of radially extending partition plates. Fluidized fluidized kiln. 7. Claims characterized in that a duct for supplying air and a gas fuel supply pipe for supplying gas fuel are alternately connected to each of the plurality of divided space parts below the dispersion means. A fluidized fluidized kiln for cement clinker and the like as described in item 6.